A liquid-ejecting head includes a pressure-generating chamber communicating with a nozzle opening, and a piezoelectric element. The determining of insulation defects is effected by way of a differential voltage of part voltages of an intermediate circuit or the ratio of one of these part voltages to the total voltage of an intermediate circuit, and by way of an operating condition of the inverter. Additionally, isolated cuts can be reinforced with assist bars to ensure that the cut clears the unexposed regions left by phase conflicts. Also, a pin extends radially inwardly from the ring, the pin engaging a hole defined by the peripheral edge of the blanket.